Esophageal pH monitoring

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Esophageal pH monitoring
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pH-probe for measuring acidity in gastrointestinal tract
MeSH D050782
OPS-301 code 1-316
MedlinePlus 003401

Esophageal pH monitoring is the current gold standard for diagnosis of gastroesophageal reflux disease (GERD). It provides direct physiologic measurement of acid in the esophagus and is the most objective method to document reflux disease, assess the severity of the disease and monitor the response of the disease to medical or surgical treatment. It can also be used in diagnosing laryngopharyngeal reflux.

Contents

Background

The importance of refluxed gastric contents in the pathogenesis of GERD was emphasized by Winkelstein who introduced the term "peptic esophagitis" and by Bernstein and Baker who reported the symptom of heartburn following instillation of hydrochloric acid in the distal esophagus in what then became known as the acid perfusion test. Formal measurement of acid in the esophagus was first described in 1960 by Tuttle. He used a glass pH probe to map the gastroesophageal pH gradient, and demonstrated a sharp gradient in normal subjects and a gradual, sloping gradient in patients with esophagitis. Four years later, Miller used an indwelling esophageal pH electrode to continuously measure esophageal and gastric pH for a period up to 12 hours. This technique required that the patient keep their hands immersed in saline to serve as a reference. Prolonged monitoring became feasible in 1974 when Johnson and DeMeester developed a dependable external reference electrode. [1] Using this technique to monitor esophageal acid exposure patients for periods up to 24 hours, DeMeester and Johnson were able to identify the most important parameters of esophageal acid exposure, and they developed a composite pH score to quantify gastroesophageal reflux. The initial 24-hour pH studies required hospitalization until the introduction of microcircuits in the 1980s that allowed portable esophageal pH monitoring in an outpatient setting.[ citation needed ]

Clinical application

Gastroesophageal reflux disease (GERD) is a common disease in western countries. In the United States, 7% of the population experiences heartburn daily and 44% at least once a month. [2] Heartburn occurs when esophageal mucosa is exposed to the acidic gastric content, but the complaint of heartburn is not always a reliable guide to the presence of acid reflux in the esophagus. [3] Further, only half of the patients with increased esophageal acid exposure will have esophagitis. [4] Therefore, the diagnosis of gastroesophageal reflux disease (GERD) on the basis of symptoms or endoscopic findings is problematic.[ citation needed ]

Although there remains no gold standard for the diagnosis of GERD, ambulatory esophageal pH monitoring can provide data to guide further evaluation and treatment of patients with GERD-associated symptoms. In the past, an indwelling nasoesophageal catheter was the only way to measure esophageal acid exposure. Because this method is associated with nasal and pharyngeal discomfort and rhinorrhea, patients may have limited their activity and become more sedentary during the monitored period. [5] This may have resulted in less acid reflux and a false negative test. A catheter-free radio telemetric system allows a longer period of monitoring and may be better tolerated. [6]

Techniques

96 Hour Bravo pH monitoring A sample of Bravo pH tracing recorded over 48 hours Bravo tracing.jpg
96 Hour Bravo pH monitoring A sample of Bravo pH tracing recorded over 48 hours

Esophageal pH monitoring is currently performed using one of the following three techniques:

  1. Single sensor pH monitoring using a pH catheter
  2. Dual sensor pH monitoring using a pH catheter
  3. Wireless pH monitoring using Bravo pH capsule or OMOM pH monitoring capsule

The duration of the test is 24 hours in the first and second techniques and 48 hours for the Bravo capsule or more (96 hours) for OMOM capsule.

pH sensor location and probe placement

In assessment of distal esophageal pH, the sensor is placed 5 cm above the upper border of the lower esophageal sphincter (LES) determined by esophageal manometry. To measure proximal esophageal acid exposure, the second sensor is placed 1-5 below the lower border of the upper esophageal sphincter (UES). The Bravo pH capsule is placed either transnasally based on manometric measurements, or following endoscopy. In transnasal placement, the capsule is placed 5 cm above the upper border of the LES, and in endoscopic placement 6 cm above the gastroesophageal junction. The same applies to OMOM pH monitoring capsule.

Components of esophageal pH monitoring

A reflux episode is defined as esophageal pH drops below four. Esophageal pH monitoring is performed for 24 or 48 hours and at the end of recording, a patient's tracing is analyzed and the results are expressed using six standard components. Of these 6 parameters, a pH score called Composite pH Score or DeMeester Score has been calculated, which is a global measure of esophageal acid exposure. A Demeester score > 14.72 indicates reflux. [7]

Components of 24-h Esophageal pH Monitoring
Percent total time pH < 4
Percent Upright time pH < 4
Percent Supine time pH < 4
Number of reflux episodes
Number of reflux episodes ≥ 5 min
Longest reflux episode (minutes)

Multichannel intraluminal impedance (MII) pH monitoring

The widespread prescription of proton pump inhibitors (PPI) by primary care physicians has resulted in a change in pattern of GERD in patients who use these medications. Quite often gastroenterologist and foregut surgeons receive consultations to assess patients with persistent reflux symptoms despite the fact that patients is on acid suppression medications. This is due to the fact that symptoms of these patients are the results of weak acid or non-acid reflux. In 1991 Silny was the first investigator who described Multichannel Intraluminal Impedance (MII), a technique which detects intraesophageal bolus transport. This method is based on measuring the resistance to alternating current (i.e., impedance) of the content of the esophageal lumen. MII- pH monitoring was then developed by several clinical investigators. [8] The clinical application of this technique is mainly in GERD patients who have persistent symptoms despite medical therapy.[ citation needed ]

pH monitoring in laryngopharyngeal reflux

Retrograde flow of gastric contents to the upper aerodigestive tract causes a variety of symptoms such as cough, asthma and hoarseness. These respiratory manifestations of the reflux disease are commonly called laryngopharyngeal reflux (LPR) or extraesophegeal reflux disease (EERD). Distal esophageal pH monitoring has been used as an objective test to establish reflux as the cause of the atypical reflux symptoms, but its role in causally associating patients' symptoms to GERD is controversial. In an effort to improve diagnostic accuracy of testing, a catheter with two pH sensors has been used to measure the degree of esophageal acid exposure in both distal and proximal esophagus. The ideal location for pH measurement to confirm the diagnosis of the laryngopharyngeal reflux is the pharynx and new studies have focused on the development of a new pH sensor which can function in the challenging environment of the oropharynx. [9]

See also

Related Research Articles

<span class="mw-page-title-main">Esophagus</span> Vertebrate organ through which food passes to the stomach

The esophagus or oesophagus, colloquially known also as the food pipe, food tube, or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 cm (10 in) long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω + ἔφαγον.

<span class="mw-page-title-main">Esophageal achalasia</span> Rare, incurable, progressive motility disorder due to failure of esophogeal motor neurons

Esophageal achalasia, often referred to simply as achalasia, is a failure of smooth muscle fibers to relax, which can cause the lower esophageal sphincter to remain closed. Without a modifier, "achalasia" usually refers to achalasia of the esophagus. Achalasia can happen at various points along the gastrointestinal tract; achalasia of the rectum, for instance, may occur in Hirschsprung's disease. The lower esophageal sphincter is a muscle between the esophagus and stomach that opens when food comes in. It closes to avoid stomach acids from coming back up. A fully understood cause to the disease is unknown, as are factors that increase the risk of its appearance. Suggestions of a genetically transmittable form of achalasia exist, but this is neither fully understood, nor agreed upon.

Heartburn, also known as pyrosis, cardialgia or acid indigestion, is a burning sensation in the central chest or upper central abdomen. Heartburn is usually due to regurgitation of gastric acid into the esophagus. It is the major symptom of gastroesophageal reflux disease (GERD).

<span class="mw-page-title-main">Gastroesophageal reflux disease</span> Medical condition

Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases in which stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/or complications. Symptoms include dental corrosion, dysphagia, heartburn, odynophagia, regurgitation, non-cardiac chest pain, extraesophageal symptoms such as chronic cough, hoarseness, reflux-induced laryngitis, or asthma. In the long term, and when not treated, complications such as esophagitis, esophageal stricture, and Barrett's esophagus may arise.

<span class="mw-page-title-main">Barrett's esophagus</span> Medical condition

Barrett's esophagus is a condition in which there is an abnormal (metaplastic) change in the mucosal cells lining the lower portion of the esophagus, from stratified squamous epithelium to simple columnar epithelium with interspersed goblet cells that are normally present only in the small intestine and large intestine. This change is considered to be a premalignant condition because it is associated with a high incidence of further transition to esophageal adenocarcinoma, an often-deadly cancer.

<span class="mw-page-title-main">Esophagitis</span> Medical condition

Esophagitis, also spelled oesophagitis, is a disease characterized by inflammation of the esophagus. The esophagus is a tube composed of a mucosal lining, and longitudinal and circular smooth muscle fibers. It connects the pharynx to the stomach; swallowed food and liquids normally pass through it.

<span class="mw-page-title-main">Hiatal hernia</span> Type of hernia

A hiatal hernia or hiatus hernia is a type of hernia in which abdominal organs slip through the diaphragm into the middle compartment of the chest. This may result in gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux (LPR) with symptoms such as a taste of acid in the back of the mouth or heartburn. Other symptoms may include trouble swallowing and chest pains. Complications may include iron deficiency anemia, volvulus, or bowel obstruction.

Coffee ground vomitus refers to a particular appearance of vomit. Within organic heme molecules of red blood cells is the element iron, which oxidizes following exposure to gastric acid. This reaction causes the vomitus to look like ground coffee.

<span class="mw-page-title-main">Nissen fundoplication</span> Surgical procedure to treat gastric reflux and hiatal hernia

A Nissen fundoplication, or laparoscopic Nissen fundoplication when performed via laparoscopic surgery, is a surgical procedure to treat gastroesophageal reflux disease (GERD) and hiatal hernia. In GERD, it is usually performed when medical therapy has failed; but, with a Type II (paraesophageal) hiatus hernia, it is the first-line procedure. The Nissen fundoplication is total (360°), but partial fundoplications known as Thal, Belsey, Dor, Lind, and Toupet fundoplications are alternative procedures with somewhat different indications and outcomes.

<span class="mw-page-title-main">Eosinophilic esophagitis</span> Allergic inflammatory condition of the esophagus

Eosinophilic esophagitis (EoE) is an allergic inflammatory condition of the esophagus that involves eosinophils, a type of white blood cell. In healthy individuals, the esophagus is typically devoid of eosinophils. In EoE, eosinophils migrate to the esophagus in large numbers. When a trigger food is eaten, the eosinophils contribute to tissue damage and inflammation. Symptoms include swallowing difficulty, food impaction, vomiting, and heartburn.

Esophageal dysphagia is a form of dysphagia where the underlying cause arises from the body of the esophagus, lower esophageal sphincter, or cardia of the stomach, usually due to mechanical causes or motility problems.

Stretta is a minimally invasive endoscopic procedure for the treatment of gastroesophageal reflux disease (GERD) that delivers radiofrequency energy in the form of electromagnetic waves through electrodes at the end of a catheter to the lower esophageal sphincter (LES) and the gastric cardia – the region of the stomach just below the LES. The energy heats the tissue, ultimately causing it to swell and stiffen; the way this works was not understood as of 2015, but it was thought that perhaps the heat causes local inflammation, collagen deposition and muscular thickening of the LES and that it may disrupt the nerves there.

Esophageal spasm is a disorder of motility of the esophagus.

<span class="mw-page-title-main">Esophageal stricture</span> Medical condition

A benign esophageal stricture, or peptic stricture, is a narrowing or tightening of the esophagus that causes swallowing difficulties.

Biliary reflux, bile reflux (gastritis), duodenogastroesophageal reflux (DGER) or duodenogastric reflux is a condition that occurs when bile and/or other contents like bicarbonate, and pancreatic enzymes flow upward (refluxes) from the duodenum into the stomach and esophagus.

<span class="mw-page-title-main">Laryngopharyngeal reflux</span> Medical condition

Laryngopharyngeal reflux (LPR) is the retrograde flow of gastric contents into the larynx, oropharynx and/or the nasopharynx. LPR causes respiratory symptoms such as cough and wheezing and is often associated with head and neck complaints such as dysphonia, globus pharyngis, and dysphagia. LPR may play a role in other diseases, such as sinusitis, otitis media, and rhinitis, and can be a comorbidity of asthma. While LPR is commonly used interchangeably with gastroesophageal reflux disease (GERD), it presents with a different pathophysiology.

<span class="mw-page-title-main">Impedance–pH monitoring</span>

Impedance–pH monitoring is a technique used in the diagnosis of gastroesophageal reflux disease (GERD), by monitoring both impedance and pH.

Reflux is a distillation technique involving the condensation of vapors and the return of this condensate to the system from which it originated.

Acid perfusion test, also called the Bernstein test, is a test done to reproduce the pain when the lower esophagus is irrigated with an acid solution in people with GERD.

<span class="mw-page-title-main">Lymphocytic esophagitis</span> Medical condition

Lymphocytic esophagitis is a rare and poorly understood medical disorder involving inflammation in the esophagus. The disease is named from the primary inflammatory process, wherein lymphocytes are seen within the esophageal mucosa. Symptoms of the condition include difficulty swallowing, heartburn and food bolus obstruction. The condition was first described in 2006 by Rubio and colleagues. Initial reports questioned whether this was a true medical disorder, or whether the inflammation was secondary to another condition, such as gastroesophageal reflux disease.

References

  1. ↑ Johnson LF, Demeester TR (October 1974). "Twenty-four-hour pH monitoring of the distal esophagus. A quantitative measure of gastroesophageal reflux". Am. J. Gastroenterol. 62 (4): 325–32. PMID   4432845.
  2. ↑ Talley NJ, Zinsmeister AR, Schleck CD, Melton LJ (April 1992). "Dyspepsia and dyspepsia subgroups: a population-based study". Gastroenterology. 102 (4 Pt 1): 1259–68. doi:10.1016/0016-5085(92)90764-P. PMID   1551533.
  3. ↑ Tefera L, Fein M, Ritter MP, et al. (October 1997). "Can the combination of symptoms and endoscopy confirm the presence of gastroesophageal reflux disease?". Am Surg. 63 (10): 933–6. PMID   9322676.
  4. ↑ DeMeester TR, Peters JH, Bremner CG, Chandrasoma P (1999). "Biology of gastroesophageal reflux disease: pathophysiology relating to medical and surgical treatment". Annu. Rev. Med. 50: 469–506. doi:10.1146/annurev.med.50.1.469. PMID   10073290.
  5. ↑ Fass R, Hell R, Sampliner RE, et al. (November 1999). "Effect of ambulatory 24-hour esophageal pH monitoring on reflux-provoking activities" (PDF). Dig. Dis. Sci. 44 (11): 2263–9. doi:10.1023/A:1026608804938. PMID   10573372. S2CID   20505417.
  6. ↑ Ayazi S, Lipham JC, Portale G, et al. (January 2009). "Bravo catheter-free pH monitoring: normal values, concordance, optimal diagnostic thresholds, and accuracy". Clin. Gastroenterol. Hepatol. 7 (1): 60–7. doi: 10.1016/j.cgh.2008.08.020 . PMID   18976965.
  7. ↑ Neto RL, Herbella FM, Schlottmann F, Patti MG (May 2019). "Does DeMeester score still define GERD?". Diseases of the Esophagus. 32 (5). doi: 10.1093/dote/doy118 . PMID   30561585.
  8. ↑ Tutuian R, Vela MF, Shay SS, Castell DO (September 2003). "Multichannel intraluminal impedance in esophageal function testing and gastroesophageal reflux monitoring". J. Clin. Gastroenterol. 37 (3): 206–15. doi:10.1097/00004836-200309000-00004. PMID   12960718.
  9. ↑ Ayazi S, Lipham JC, Hagen JA, et al. (August 2009). "A new technique for measurement of pharyngeal pH: normal values and discriminating pH threshold". J. Gastrointest. Surg. 13 (8): 1422–9. doi:10.1007/s11605-009-0915-6. PMID   19421822. S2CID   8736410.
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